Safety igniter



May 13, 1924.

. E. P. JONES ET AL SAFETY IGNIIER Filed Nov. 6, 1923 Patented May 13,1924.

UNITED STATES PATENT OFFICE.

EDWARD I. JONES, DANIEL W. FALL, AND FRANCIS EDWARD JONES, OF BRECKEN-RIDGE, COLORADO.

SAFETY IGNITER.

Application filed November 6, 1923. Serial No. 673,086.

To all whom it may concern:

Be it known that EDWARD P. J ONES, DAN- IEL l/V. FALL, and FRANCIS E.Jones, citizens of the United States, residing at Breckenridge, in thecounty of Summit and State of Colorado, have invented certain new anduseful Improvements in Safety Igniters, of which the following is aspecification.

The present invention relates to safety igniters for all sorts of highexplosives, such for example as are used in blasting, mining and likeoperations.

An object of the invention is to provide a safety igniter structureembodying and retaining the most important features of the igniterdisclosed in copending application Serial No. 660,635 filed Sept. 1,1915, and which may be more readily and cheaply manufactured.

Another object of the invention is to provide a new, eliicient and cheapmethod of manufacturing igniters of standard dimensions, but of variabletiming.

Further objects of the invention will appear in the following detaileddescription of the preferred embodiments of the invention of which-Figs. 1, 2 and 3 are sectional elevations of different forms with partsbroken away to disclose the structure, and

Figs. 4, 5, and 6, are plan views of the forms shown in Figs. 1, 2, and3 respectively.

Referring to Figs. 1 and 4, 1 represents a hollow tube which may be ofany flexible noncombustible material, but is preferably of metal, suchfor example, as copper, lead, or like metals. In practice, tube 1 may beof any length and is filled with powder or like combustible materialswhile straight, and is then preferably wound into along helix. This longhelix may then be cut into proper lengths to give desired time trainsfor variously timed igniters. It will be ob vious that with standarddimensions for the igniter, for a given length of fuse the maxi mum timewill be given when the turns of the helix are in contact with eachother, and the shortest time will be attained for the standard length,when the tube 1 is substantially straight. Between these limits, a widerange of timing is possible.

Having out time train 1 to proper length, the ends are preferably dippedinto wax, paraffin or like easily fusible materials to hold the fillingin place and the upper end thereof is inserted in a washer 2 preferablyof noninetallic and noncombustible material. lhe washer is then fittedinto ahollow tube 3. Tube 3 is of noncombustible and of preferablynonmetallic material, and may be shouldered if desired, to maintainwasher 2 in the proper position until the igniter has been completed.The lower end of train 1 is then held in proper position to reach thelower end of tube 3, and a filling 4 of cement, paste, parafiin, wax, orlike materials, which may be liquefied at a temperature sufficiently lowto prevent ignition of the combustible material in tube 1, is pouredaround tube 1 into tube 3 and permitted to solidify. After 4 hashardened sufliciently to hold tube 1 in place, the lower end may bedipped in wax or like materials to seal the end of the igniter. Afilling 5 of powder of like combustible material is then placed in theupper end of tube 3.

plug 6 of paste, cement, or like materials in which are imbeddedconductors 7 and 8, is then inserted in and seals the upper end of tube3, the ends of conductors 7 and 8 being bent to form a pair of sparkpoints across which an electrical spark may be passed to ignite material5. Wires 7 and 8 are properly insulated from each other, and adapted tobe connected to a source of electrical energy in well known manner.

In the form shown in Fig. 2 the method of manufacture and parts are thesame as for the form shown in Fig. 1, except that washer 2 is replacedby a member 2, preferably of nonmetallic and noncombustible materialswhich is shaped to make a chamber for material 5. The upper end of tube1 is inserted only partially through the opening in 2 to avoidpossibility of an accidental ground igniting the powder train by jumping'a spark from either terminal 7 or 8 to the metallic: tube 1, and toavoid accidental interference with the spark across 7 and 8.

In the form shown in Fig. 3, members 2, 2 and 3 are eliminated, andmaterial 1 is molded around tube 1 in a manner to provide a chamber formaterial 5 and with which the upper end of tube 1 communicates. Plug 6is applied as before.

It will be seen that simple forms of, safety i 'niters are providedwhich may be cheaply manufactured according to the method of the presentinvention in Whichallpossibility of hanging fire is eliminated, and inwhich a Wide ariation oftiming for a standard length of igniter may beprovided. It will of course be understood that the ignit'e'rs are to beproperly marked to indicate the timing thereof and may be applied to "acap as disclosed in the copending case.

laving described preferred embodiments of the invent-ion, What is.desire dto be secured by Letters Patent and claimed as new is: v V

1. A safety igniter comprising a body of standard length and solidmaterial, in which a tubular helix of rapidly combustible material isimbedded; a chamber With which the upper end of said helix communicates,combnstible material in said chamber, and means for igniting saidcombustible material sealed in said chamber.

2. The igniter as set forth in claim 1 in which said body is confined ina protective outer tube.

3. The igniter as set forth in claim 1 together with a base member forsaid chamber.

EDWARD P. JONES. FRANCIS EDWARD JONES. DANIEL W. FALL.

